fstab-generator: Do not try to fsck non-devices

This fixes a regression introduced in 64e70e4 where the mount fails
when fstab is misconfigured with fs_passno > 0 on a virtual file
system like nfs, and the type is specified as "auto".
logind: remove dead variable

Noticed-by: Jan Alexander Steffens <jan.steffens@gmail.com>